Dendreon’s pivotal clinical trial is standing up to the test of time—and it may need that sort of analysis to fend off a tough new competing chemo drug. The Seattle-based biotech company (NASDAQ: DNDN) said today that its first-of-a-kind immune booster for prostate cancer helped men live longer than a placebo, after another couple extra months of follow-up than was previously reported.
Researchers reported new data from the study known as “Impact,” which enrolled 512 men with prostate cancer that had spread after earlier treatment with hormone-blocking agents. Men who got sipuleucel-T (Provenge) lived a median of 4.1 months longer than those in the control group who got a placebo—the same differential Dendreon reported last year. This new finding was reached after 36.5 months of follow-up time, or about an extra 2.4 months of follow-up beyond what Dendreon reported last April at the American Urological Association meeting. The new results are being presented at the American Society of Clinical Oncology’s Genitourinary Cancers Symposium in San Francisco.
Those following the Dendreon story know that the survival advantage enabled the company to raise more than $600 million last year, embark on an ambitious hiring and manufacturing plan, and whip up a new drug application to the FDA. The company is hoping that the FDA will approve the immune-booster by its deadline of May 1, and that the new data will help win the hearts and minds of urologists and oncologists who might prescribe it.
While the latest data batch doesn’t really draw any new conclusions, it’s an important confirmation for a company that’s sure to face strong competition as it enters the market. Paris-based Sanofi-Aventis, for one, reported that a modified chemotherapy drug it calls cabazitaxel (kuh-BAH-zuh-TAX-uhl) was able to prolong lives for a median of 10 weeks in patients who had run out of options after they got a prior round of docetaxel (Taxotere) chemotherapy, and their disease spread anyway.
The Sanofi finding, from a trial of 755 men, is important for prostate cancer patients, but not a serious competitive threat to Dendreon, says David Miller, president of Seattle-based Biotech Stock Research and a longtime Dendreon bull. That’s because a chemotherapy drug carries more severe side effects than Dendreon’s treatment, which causes mild to moderate fever and chills that last a couple days. And the therapy from the Seattle biotech company will likely be prescribed for patients with an earlier stage of disease than those who enrolled in the latest Sanofi trial. The “Impact” study enrolled people whose disease had spread after they stopped responding to hormone blockers—not patients who had already relapsed after a round of chemotherapy.
“We have learned from Taxotere that guys with prostate cancer don’t want the side effects,” Miller says. “Guys will get Provenge first and something else later.”
Still, Miller acknowledges that the data from Sanofi is impressive. The patients who got cabazitaxel saw tumor shrinkage; improvement in their PSA scores (a common diagnostic marker of prostate cancer severity; and it was able to keep tumors from spreading for a longer period of time. Patients on the new Sanofi drug and prednisone (an immune suppressor) lived a median time of 15.1 months, which was a statistically significant advantage over those in the control group who lived 12.7 months on mitoxantrone (a chemo agent) and prednisone. Men on the new Sanofi drug were more likely than those in the mitoxantrone group to have a serious form of fever and white-blood cell depletion known as febrile neutropenia. About 7.5 percent on the Sanofi drug had that side effect, compared with 1.3 percent in the control group.
An estimated 27,000 men in the U.S. die each year from prostate cancer, according to the American Cancer Society.
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